1. Field of the Invention
The present invention relates to a polyphenylene sulfide resin composition with improved impact resistance and a process for preparing the same.
The polyphenylene sulfide resin composition can be used as a sealing material for electronic parts, a material for producing electric and electronic parts, a material for automobile parts, a heat resistant coating or connector parts.
2. Description of the Related Art
A polyphenylene sulfide resin is one of engineering plastics having excellent heat resistance, chemical resistance and electric properties and is used in various fields. However, the polyphenylene sulfide resin has poor toughness and insufficient mechanical properties, in particular, impact resistance. Therefore, its application for a structural part which requires good mechanical properties or a sealing material in which generation of stress-strain is prevented during sealing, or in the fields where flexibility is required is largely limited.
In general, to reduce stress of a resin, a flexible polymer is blended with the resin. It is proposed to blend the polyphenylene sulfide resin with a fluorine-containing elastomer as a flexible polymer which has heat resistance and chemical resistance and does not deteriorate good heat resistance and chemical resistance of the polyphenylene sulfide so as to improve impact resistance (see Japanese Patent Publication No. 202344/1982). In this blend, dispersibility of the fluorine-containing elastomer in the polyphenylene sulfide is insufficient, and improvement of the impact resistance is unsatisfactory. In addition, the mechanical properties of the polyphenylene sulfide resin are deteriorated.
It is proposed to blend the polyphenylene sulfide resin with a fluorine-containing thermoplastic elastomer to improve the impact resistance (see Japanese Patent Kokai Publication No. 218446/1987). In this blend, the dispersibility is insufficient and improvement of the impact resistance is unsatisfactory. In addition, the fluorine-containing thermoplastic elastomer is expensive.
In the blend of the polyphenylene sulfide resin with the flexible polymer, the latter is preferably finely dispersed in the former. In this respect, the fluorine-containing polymer is not sufficiently dispersed in the polyphenylene sulfide resin.
To improve the dispersibility of the blend, a compatibilizer can be added to the blend. In case of the mixture of the polyphenylene sulfide resin and the fluorine-containing elastomer, there is no compatibilizer having heat resistance and chemical resistance.